BoilerFaultCodesYour boiler is struggling to ignite and has reached its limit of failed attempts to start up.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Number of unsuccessful lockouts
What causes this fault?
This fault occurs when the boiler has repeatedly failed to light or detect a flame, causing the system to lock itself out for safety after five unsuccessful attempts. It is usually caused by a lack of gas supply, a worn-out ignition spark, or a component failure that prevents the burner from sustaining a flame.
This issue is more frequent during the first cold snap of winter when components that have been idle all summer are suddenly under high demand and fail to cooperate.
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
Find a Gas Safe engineer
Search the official register for a qualified engineer in your area.
Gas Safe Register →Protect yourself from future repair bills
A boiler cover plan would cover faults like D.61 — no call-out fees, no surprises.
Affiliate links — we may earn a commission at no extra cost to you.
Could it be time for a new boiler?
If repair costs are adding up, a new energy-efficient boiler could be the smarter long-term choice.
Affiliate links — we may earn a commission at no extra cost to you.